Photosensitive apparatus for inspecting materials



J 4 F. H. GULLIKSEN 2,229,451

PHOTOSENSITIVE APPARATUS FOR INSPECTING MATERIALS Filed April 18, 1939 1 WITNESSES: INVENTOR 65 1 27277 A! Gulli/fsen.

ATTO EY Jun. 21, 194:

91TH!) STATES PATENT. OFFICE momseusrnvn APPARATUS roe IN- srscmc MATERIALS I- Glllhin. Pittsburgh, Pa., assignor to Ioctric & Manufacturing Com- Pa, a corporation of by radiant enemy. the intensity of chains.

abbot of my invmtion is to pmvide a radiant energy clutter particularly adapted for use with a photoresponsive device actuable tensity.

A iurther ancillary object of my invention is to provide a radiant energy emitter devoid of any moving parts for use with a photoresponsive device actuable only by radiant energy which is varying in intensity.

More concisely stated, it is an object of my invention to provide a photosensitive classifying M3 to my invention, I provide a classii'ying arrangement in which the intensity of the radiant energy projected on the surface of the sheet metal to be classified has a constant component on which a variable, preferably periodic, component is superimposed. In cooperation with the radiant energy source, a dynamic photoelectric amplifier is used. I'he latter responds only to varying radiant energy, the time rate of change of which is substantially smaller than the rate corresponding to the varying component of the radiant energy. When the sheet metal is moving at a high speed an instantaneous, abrupt increase in the excitation of the photoddraylighhasocalled -b inlieuotastatic am- .Iifler responds only to A M at I predetermined I tor cmstant or slowly MI- With such an ampli m m is produced unless a lhlmtchamre in the radiant My invention has been described herein as specifically applied to the detection of holes in sheet metal merely for the purpose of illustrating its utility and not with any intention of limiting its scope. Where my invention is used in connec- I specific embodiments of my invention, I am fully aware that any modifications thereof are possible. My invention, therefore, is not to be restricted except in so far as it is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In combination, photosensitive means responsive to a change in radiant energy impinging thereon, which has a time rate greater than a predetermined rate, a source of radiant energy, of the type forwhich the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photosensitive means and means for impressing alternate halfcycles of potential on said source.

2. For use with an alternating current supply, the combination comprising photosensitive means responsive to a change in radiant energy impinging thereon, having a time rate greater than a predetermined rate, a source of radiant energy, of the type for which the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photosensitive means and means for impressing alternate halfcycles of potential from said supply on said source.

3. For use with an alternating current supply, the combination comprising photosensitive means responsive to a change in radiant energy impinging thereon, having a time rate greater than a predetermined rate, a source of radiant energy,

of the type for which the intensity of radiant energy emitted varieswith the potential imthe combination comprising photosensitive means responsive to a change in radiant energy impinging thereon, having a time rate greater than a predetermined rate, a source of radiant energy, of the type for which the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photosensitive means and circuit means having current rectifying means interposed therein for energizing said source from said supply, said predetermined rate being substantially less than the rate of change in the radiant energy produced by the normal cyclic potential variations of said source.

5. For use with a 60 cycle alternating current supply, the combination comprising photosensitive means responsive to a change in radiant energy impinging thereon, having a time rate great- ,1 er than a predetermined rate, a source of radiant ing thereon, having a time rate greater than that corresponding to a frequency substantially smaller than the frequency of said supply, a source of radiant energy, of the type for which the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photosensitive means and circuit means having rectifying means interposed therein for energizing said source from said supply.

7. For use with a 60 cycle alternating current supply, the combination comprising photosensitive means responsive to a change in radiant energyimpinglng thereon, having a time rate greater than that corresponding to a frequency of the order of one cycle per second, a source of 1 radiant energy having an incandescent filament tric discharge valve having input and output.

electrodes, a capacitor for coupling said cell to said valve, an arc-dike electric discharge valve having input and output circuit and another capacitor for coupling the output circuit of said first-mentioned valve .to the input circuit of said last-mentioned valve, a source of radiant energy, of the type for which the intensity of radiant energy emitted varieswith the potential impressed, disposed to energize said photosensitive means and vary the conductivity of said lastmentioned valve and circuit means having haliwave rectifying means interposed therein for energizing said source from said supply.

9. For use with an alternating current supply, the combination comprising photosensitive means responsive to a change in radiant energy impinging thereon, having a time'rate greater than that corresponding to a frequency substantially smaller than the frequency of said supply, and comprising a photoelectric cell, a high vacuum electric discharge valve having input and output electrodes, a capacitor for coupling said cell to said valve, an arc-like electric discharge valve having input and output circuits, another capacitor for coupling the output circuit of said first-mentioned valve to the input circuit of said last-mentioned valve and means for impressing a direct potential derived from said source in the output circuit of said last-mentioned valve, a source of radiant energy, of the type for which the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photosensitive means and render said last-mentioned valve conductive and means responsive to the current conducted by said lastmentioned valve for rendering said last-mentioned valve non-conductive and circuit means having half-wave rectifying means interposed therein for energizing said source from said sup- P y- 10. For use in classifying material that may move at different speeds, the combination comprising a source of radiant energy,'the intensity of which has an appreciably constant component on which is superimposed an appreciable periodic component, means for subjecting said material in motion to said source, and photosensitive means responsive to the resultant radiant energy emitted by said material and actuable by a change in radiant energy impinging thereon, said change in radiant energy having a time rate substantially greater than the frequency of said periodic component.

11. For use with an alternating current supply, the combination comprising a photoelectric cell, a high vacuum electric discharge valve having input'and output electrodes, a capacitor for coupling said cell to said valve, an arc-like electric discharge valve having input and output circuit and another capacitor for coupling the output circuit of said first-mentioned valve to the input circuit of said last-mentioned valve, a source of radiant energy, of the type for which the intensity of radiant energy emitted varies with the potential impressed, disposed to energize said photoelectric cell and vary the conductivity of said last-mentioned valve and circuit means having half-wave rectifying means interposed therein for energizing said source from said supply.

12. In combination photosensitive means responsive only to a change in the radiant energy impinging thereon, a source. of radiant energy of the type for which the intensity of the radiant energy emitted varies with the potential impressed and circuit means adapted to pass alternate half-cycles of an alternatingpotential for supplyin potential to said source. 7

13. For use in classiiying material that may move at difl'erent speeds, the combination comprising a source of radiant energy, the intensity of which changes continually, said source of radiant energy including an emitter having an incandescent filament and a circuit for supplying current to said emitter adapted to pass alternate half-cycles from an alternating current source,

means for subjecting said material in motion to said source, and photosensitive means actuable only by a change in radiant energy impinging thereon responsive to the resultant radiant energy emitted by 'said material.

14. For use in detecting perforations in moving sheet material, the speed of which may vary over a wide range, the combination comprising means for projecting on one surface of said sheet radiant energy, the intensity of which has an appreciable constant component on which a variable component is superimposed, and photosensitive means disposed to receive the resultant radiant energy which penetrates perforations in said sheet, said photosensitive means being actuable by a change in radiant energy impinging thereon having a time rate, such that for a perforation in sheet moving at a speed smaller than a predetermined speed it is actuated by reason of said variable component in said radiant energy and for a perforation in a sheet moving at a speed greater than said predetermined speed it is actuated by reason of the change in said radiant energy produced by the movement of said sheet.

15. For use in classifying material that may move at diiierent speeds, the combination comprising agource oi radiant energy, the intensity of which has an appreciable constant component on which is superimposed an appreciable variable component, means for subjecting said material in motion to said source, and photosensitive means responsive to the resultant radiant energy emitted by said material and actuable by a change in radiant energy impinging thereon, said change in radiant energy having a time rate substantially greater than the time rate-of change of said variable component.

j FINN H. GULIIKSEN.

Jan. 28, 1941.

C. F. RAUEN.

MUFFLER Original Filed Feb. 10, 1930 

